Historical coastal urban development established buildings and civil structures along shorelines and extending to the water's edge, eliminating the critical transition of the tidal zone. Features of urban edges, such as seawalls or rigid pile structures, are exposed to wave energy, which causes scour and increases erosion rates near cities. These large-scale urban edges eliminate protective landscape features, which exacerbates the effects of sea level rise (overexposure to storm waves) and environmental catastrophe (hurricane or tsunami). In contrast to this, native shoreline ecosystems stabilize the shoreline with interconnected root structures and compliant features that absorb and dissipate wave energy.
Numerous prior art structures and devices have been devised to reduce or eliminate the tendency for shoreline erosion caused by waves varying in strength from normal wave action to storm or hurricane levels. Recently, more emphasis has been placed on the conservation of the natural shorelines as changing weather patterns and rising sea levels have increasingly effected the rate of coastal erosion. Several conventional planning approaches exist that attempt to manage the range of movement typical for a coastal zone. These approaches include: conservation, artificial barrier islands, wetland establishment, coastal re-alignment, shoreline reclamation/beach nourishment, and seawall/bulkhead construction.
Many of the known methodologies seek to provide wave energy absorption and dissipation by incorporating one or more of wave reflection (counter-force) and refraction (change in angular direction). Some existing approaches for coastal remediation also attempt to preserve native vegetation and incorporate such flora into the erosion prevention scheme. Various coastal vegetations have been considered in this regard. For example, systems employed in tropical climates have sought to preserve and incorporate mangrove forests. Studies have shown that mangrove ecosystems are being lost faster than the rainforests. These intertidal forests are essential to complex land and marine ecosystems and responsible for filtering agricultural and urban runoff, primary fish habitats, and biodiversity linked to a complex network of ecological criteria. Native littoral zone ecosystems (including, for example, mangrove and sea grass) stabilize the shoreline with root structures and compliant features that absorb and dissipate wave energy.
Existing mangrove ecosystem regeneration efforts vary in scale and implementation. Mangrove seedlings are opportunistic colonizers and are typically planted directly in tidal flats. The seedlings' roots have exceptional gripping capacity and can take hold of porous substrates, such as stone or existing mangrove roots. These ecosystems are intertidal and therefore maintaining or restoring proper hydrological regime (tidal cycle) is critical to success of a replanting effort. Known remediation methodologies utilizing wave refraction seek to cause eddy turbulence to allow seedlings to settle out and take root into the soil.
One known remediation solution for mangroves is a reef ball system, utilizes a seedling planter that is placed directly in the soil and used to secure the seedling against wave energy. Additional methods to protect young seedlings utilize PVC pipes as ‘sleeves’ or bamboo stakes that hold seedlings against wave energy. All of these planters lack the vertical depth required to account for deep-water habitats that exist alongside urban features such as seawalls or bulkheads. Conventional planters can only be applied when tidal flats are present to provide the intertidal substrate necessary for mangrove seedlings. Although replanting strategies have success in some areas, conventional techniques fall short of accommodating the requirements of other regions such as urban environments.